The Brani container terminal and the Keppel container terminal stand in this aerial photograph taken above Singapore, on Thursday, July 2, 2015.

Singapore's exports in August stalled and though sales to the United States picked up, underlying weakness in overseas demand is expected to maintain pressure for further stimulus to shore up the stuttering trade-dependent economy.

Non-oil domestic exports (NODX) registered flat growth last month from a year earlier, the trade agency International Enterprise Singapore said in a statement on Friday.

While that was better than the median forecast of a 4.1 percent slump in a Reuters poll and a 10.6 percent loss in July, the overall picture was one of slack offshore demand.

On a month-on-month, seasonally adjusted basis, exports declined 1.9 percent in August, beating a forecast of a 2.9 percent fall in the survey.

"It's flat year on year for August but whether we actually get the pick up going into the fourth quarter, which is traditionally the peak season, not quite sure whether that's going to materialize in a very strong way yet," said Selena Ling, head of treasury research and strategy for OCBC Bank.

The city-state's economy has been hit by weak global demand, while domestic challenges such as a labor shortage have dragged on growth. In August, Singapore cut its 2016 economic growth forecast to 1-2 percent from the previous forecast of 1-3 percent expansion, leaving the door open for additional policy stimulus.

Exports to the United States grew 4.8 percent in August on-year, compared to a 19.1 percent decrease in July.

The recovery came on a surge in sales of non-electric engines and motors, disk media products and telecommunication equipments.

Shipments to China, Singapore's top overseas market, fell 5.4 percent in August from a year earlier, much less than a 16.6 percent decline in July. That came as the world's second-largest economy showed tentative signs of stabilization. China's factory output and retail sales grew faster than expected last month, while imports unexpectedly rose for the first time in nearly two years.

Sales to the European Union contracted 15.6 percent last month from a year earlier after a 3.0 percent growth in July.

Electronics exports in August shrank 6.0 percent from a year earlier after falling 12.9 percent in July. Volatile pharmaceutical shipments decreased 17.9 percent, compared to a 12.7 percent growth in the previous month.